Electrically ignitible power gas generating blank cartridges



Aug. 15, 1950 T. THOMSON ETAL 2,518,958

A ELECTRICALLY IGNITIBLE POWER GAS GENERTING BLANK CARTRIDGES Filed June 18, 1946 f5- iL/,ff I

f o l 6 1&3 5 'K 11 9 S INVENToRs THOMAS THGMSON JOJHN SIDNEYBHUFFLEBQTHAM ATTO RN FY Patented Aug. 15, 1950 ELECTRICALLY IGNITIBLE POWER GAS GENERATING'BLANK CARTRIDGES Thomas Thomson, Kilmarnock, Scotland, and

John S. Shulebotham, Staffordshire, Englandyassignors to Imperial Chemical Industries Limited, a corporation' of Great Britain Y Application `lune 118, 1946, Serial No. G77-,454 In Great Britain June 20, 1945 The present inventionrelates to a new or modlfied construction of electrically ignitable power gas generating blank cartridges such as are suita-ble for the generation of gases under pressure in the actuation of mechanical devices, for inl' stance internal combustion engine starter cartridges. In particular the invention relates to an improved or modified method of assembling electrically ignitable powel` gas generating blank cartridges provided with certain kindling elements, to which reference will be made hereinunder, whereby the danger of premature ignition taking place during the loading of the cartri-dge is minimised.

rIhe lcombustible gas producing charges in power gas generating blank cartridges usually consist mainly of smokeless powder forms of oo nsiderably large grain sizes that cannot be directly ignited by the electric fuzehead employed as electrical ignition means for the cartridges. More generally it may be stated that it is impracticable to employ for any substantial portion of the combustible charge a combustible material of such form or composition as to be easily ignited directly from the electric fuzehead, since otherwise the rate of combustion of such material would become excessive as the pressure increased, so that the rate cf pressure generation would become suhcient to damage the mechanism it is required to operate. A small quantity of a composition directly ignitable by the electric fuzehead is therefore used as an intermediate kindling charge, and it is frequently necessary to employ a gas producing charge comprising more than one portion of differing forms or compositions in successive ignition relationship with said intermediate kindling charge and With one another. For instance the combustible gas producing charge for an engine starter cartridge whereof the contents are intended to be ejected in ilaming condition from the cartridge case frequently comprises smokeless powder pellets of two diiering sizes or compositions, one oi which is less easily extinguished on ejection, or more easily ignited, than the other, as well as an intermediate kindling composition directly ignitable by the electric fuzehead.

In practice power gas generating blank carbridges frequently include for kindling purposes in the proximity of a fuzehead at the base of the cartridge a disc or cup of combustible material extending across the cartridge case and having a powder coating capable of direct'ignition from the fuzehead, a plurality of powder grains capable of being ignited from said coating being hap- 5 Claims'. (C1. 102-39) hazardly disposed around the fuzehead and the remainder of the combustible charge being situated on the distal side of the partition, Hitherto it has been the practice to support the disc or cup bearing the coating directly ignitable by the fuzehead, for instance a, Celluloid disc or cup coated with black powder, on the side next to the fuzehead upon the haphazardly disposed grains of smokeless powder or the like surrounding the fuzehead, which is protected by an open ended sheath. In the manufacture of such cartridges premature ignitions have sometimes been occasioned by friction occurring between the= powder coating 0n the cup or disc against the exposed end of the electric f-uzehead under the pressure employed in loading the cartridge.

According to the present invention, in the construction of electrically ignitable power gas gen'- erating blank cartridges oi the kind wherein there is provided in the proximity of an exposed portion of an electric fuzehead at the cartridge base a partition of combustible material extending across the cartridge and bearing in its proximal side a powder coating capable of direct ignition from said fuzehead and of igniting a portion of the combustible charge disposed around said fuzehead, the said partition is supported clear of the fuzehead by means of a tubular spacing member made of combustible material resting on said base.

I'he tubular spacing member may advantageously be made of smokeless powder of Celluloid and may take the form of a cylindrical annulus of outer diameter slightly less than the internal diameter of the cartridge case. It will be understood that the wall of the tubular spacing member is thin enough to allow of the haphazard disposition of grains of smokeless powder or the like around the fuzehead, which is desirably protected by means of an open-ended tubular sheath, in the space between the base of the cartridge and the coated side of the partition in direct ignition relationship with the fuzehead. The length of the tubular spacing member is suicient to ensure that even under loa-ding pressure conditions the powder coated partition will nowhere touch the exposed portion of the fuzehead, nor compress any solid particles against it.

In loading the cartridge, the tubular spacing member may be inserted into the base of the cartridge case already containing the electric fuzehead provided with its open-ended protecting sheath, the kindling powder grains may then be introduced as by pouring or running into the cartridge case in quantity insucient to extend as far as the end of the tubular spacing member. The powder coated partition may then be seated on the end of the tubular spacing member With the powder coated surface facing the exposed end of .the Vfilzahead. The Ynernainder f the combustible charge may then be loaded on the distal side of the partition and the end of the cartridge case turned over a terminal disc .of

Celluloid of other combustible material in known manner.

The invention is further illustrated in the diagrammatic `drawing accompanying the specification, which represents a lgngitudinal axial section of a power gas generating blank cartridge made in accordance with the invention. Y

In the diagrammatic drawing, lI is a `metal cartridge base having a central perforation 8. 2 and 4 are base wads of ,insulating material. 3 is a paper cartridge case wall. Il is an electric fuzehead of which one of the terminal leading strips 9 is earthed to the metal Yfraltrifige base l while the other Wholly insulated with wads 2 and 4 is exposed as a live terminal at the aperture 8. i3 is a Celluloid ring and I2 is a piece lof rubber tubing. 5 is e, Celluloid cup bearing a coating 'l -of black powder attached to it. 5 are haphazarpdly disposed smokeless powder .pellets. The powder coating 7 is capable -of direct ignition from the fuzehead Il and the pellets 5 are capable of directv ignition from the powder coating 1. I 0 is a further layer of smokeless Spowder pelletsV similar to the pellets 5. I 4 is a longitudinal perforated cylindrical rod Yof a .smokeless powder composition and l5 is a Cel,- lu-loid disc.

VWe claim: Y

1. An electrically ignitable power gas generating blank cartridge .of the kind wherein there is provided in the proximity lof an exposed por- 'tion of an electric fuzehead at the cartridge base .a partition of combustible material extending .across the cartridge and bearing on its proximal :side a powder coating capable of direct ignition from said fuzehead and of igniting a, portion of 4 a combustible charge disposed around said fuzehead having included therein a tubular spacing member made of combustible material resting on said base and supporting the said partition clear ,of the fuzehead 2. An electrically ignitable ypower gasV generating blank cartridge as claimed in claim 1 wherein the tubular spacing member is made of smokeless powder.

3. A-n electrically ignitable power gas generating blank cartridge as claimed in claim 1 wherein the tubular `spacing member is made of Celluloid.

1i. An electrically ignitable power gas generating blank cartridge as claimed in claim 1 wherein the tubular spacing member is Yin the .form of a cylindrical annulus of outer diameter slightly less than the internal diameter of the cartridge case. Y Y

5. An electrically ignitable power gas generating blankV cartridge as claimed in claim l wherein the fuzehead is protected by means of an open ended tubular sheath in the space between the base of the cartridge and the coated side of the partition.

THOMAS THOMSON. lJOHN S. SHUFFLEBOTHAM.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 682,364 Mangon Sept. V10, i 1,754,987 Driggs et al. g Apr. 15, 1,930 ,2,165,263 Holm July 11, 1939 2,362,927 Pratt Nov. 14, 1944 2,398,683 Whitworth l Apr. 16, 1946 FOREIGN PATENTS Number :Country Date 129,668 Great Britain July 24, 1919 

